1. Field of the Disclosure
This disclosure relates to wide-band acoustic transducers and methods of making and using such transducers in acoustic tools for downhole well logging and other applications.
2. Background Art
Typical downhole acoustic logging tools utilized for estimating formation properties include one or more acoustic transmitters or sources and a number of acoustic receivers. The transmitters induce acoustic energy into the formation surrounding the wellbore. The transmitted acoustic signals are reflected by interfaces associated with the formation. The reflected acoustic signals are detected by the receivers in the logging tool and processed to provide estimates of one or more properties of the formation. Majority of such transmitters operate effectively in relatively high frequency range, such as, for example, between 10 KHz to 20 KHz. The depth of investigation depends upon the frequency of the transmitted signals. In certain downhole applications it is desirable to determine formation properties at various depths, wherein a single transducer may be used over different frequency ranges, including a low frequency range, such as, for example, 1 kHz-3 kHz, mid frequency range, such as 4 KHz-8 KHz and high frequency range, such as above 10 KHz.
The disclosure herein provides acoustic transmitters that can operate over a relatively broad frequency range, including the low frequency range of 1 KHz-3 K Hz.